This invention relates to the distribution of powder products and more precisely to the subdivision of a single main stream of powder products entrained in a gas into a multiplicity of secondary streams. The invention is particularly useful for feeding secondary streams to different spots along the length of a slit nozzle for coating a substrate such as a glass plate or ribbon.
Patent No. EP0,006,064 describes an installation for coating glass in which a slit nozzle uniformly distributes a powdered metal compound onto a hot glass ribbon so as to obtain, after pyrolysis of the powder in contact with the hot glass, a coating layer having particular optical and electrical properties. The slit nozzle is fed over its entire length by a multiplicity of feed conduits formed by dividing a single primary intake pipe carrying the powder entrained in a gas.
The standard means of subdividing the single primary pipe into a multiplicity of secondary conduits are generally satisfactory. However, when the number of secondary conduits becomes too great, for example, when excellent uniformity of distribution is required, and it is necessary to feed a slit nozzle covering three or four meters in width of an industrially produced glass ribbon, these standard means may not be sufficient. Specifically, they introduce too great pressure losses and have a tendency to clog and become destabilized.